1. Field of the Invention
This invention relates to a process for the production of alkyl sulfate pastes having improved flow properties by co-sulfonation of aliphatic alcohols and unsaturated fatty acid glyceride esters and subsequent neutralization and hydrolysis of the reaction products formed.
2. Statement of Related Art
Anionic surfactants of the alkyl sulfate type, particularly those containing C.sub.16-18 alkyl radicals, show excellent detergent properties and are used in particular in powder-form detergents.
Powder detergents of the type in question are produced from water-containing alkyl sulfate pastes. In order to avoid unnecessary mass transport during spray drying, the water-containing surfactant pastes advantageously have a high solids content. However, alkyl sulfate pastes can only be concentrated to a certain solids content. Beyond this limit, their viscosity generally reaches such high values that the surfactant solutions can no longer be pumped, even at elevated temperatures.
There has been no shortage of attempts in the past to solve the problem posed by the high viscosity of anionic surfactant pastes. For example, the use of secondary alkane sulfonates and hydroxycarboxylic acid salts as viscosity-reducing agents for anionic surfactant concentrates is known from German patent applications DE-A-34 47 859 and DE-A-22 51 405. The viscosity of alkylbenzene sulfonate pastes can be reduced by alkoxylated alcohols [DE-A-37 18 896] or aliphatic hydrocarbons [DD-A-240 025]. Other known viscosity reducers are sulfonated aromatic compounds [DE-A-23 05 554], cumene sulfonate or acidic phosphoric acid esters [DE-B-16 17 160], polyhydric alcohols, carboxylic acids or esters thereof [EP-A-0 008 060] or mono and/or disulfates of polyalkylene glycol ethers [EP-B-0 024 711].
However, the viscosity reducers mentioned fail in cases where the viscosity of water-containing alkyl sulfate pastes has to be reduced.
Accordingly, the problem addressed by the present invention was to provide a process for the production of alkyl sulfate pastes having improved flow properties.